Large amounts of 1,4-butynediol are produced every year, chiefly as an intermediate in the preparation of tetrahydrofuran. In that preparation, the butynediol is hydrogenated to 1,4-butanediol, which is then dehydrated and cyclized to tetrahydrofuran.
It has been a common practice in years past to make 1,4-butynediol from acetylene and formaldehyde, using as a catalyst a copper acetylide complex. This is shown in my U.S. Pat. No. 4,110,249, in which I describe a catalyst made from malachite in the form of spheroidal masses of crystals which contain bismuth oxy-compounds to supress cuprene formation.
Such a catalyst is quite satisfactory, but I have found that its resistance to degradation by attrition can be improved if the malachite from which it is prepared also contains 0.5-3.5% by weight, of silicic acid. I have also found that the silicic acid gives the catalyst higher activity, and that this higher activity is sustained for a longer period than with my earlier catalyst.